Means for use in controlling induction-motors.



N. PENSABENE.

MEANS FOR USE IN CONTROLLING INDUCTION MOTORS APPLICATION FILED JUNE 311911.

Patented Aug. 26, 1913.

2 SHEETS-SHEET l.

N. PENSABENE.

MEANS FOR USE IN CONTROLLING INDUCTION MOTORS.

APPLICATION FILED JUNE 3, 1911.

1,071,336, Patented Aug. 26, 1913.

2 SHBETS-SHEET 2.

mooLo rnnsannnn, or mmcmenan, ENGLAND.

MEANS FOR- USE IN CONTROLLING INDUCTION-MOTORS.

Specification of Letters Patent.

Application filed June 3, 1811. Serial No. 031,110.

To all whom it may concern: Be it known that I, NICOLE Pnnsannnm; a subject of the King of Italy, and at Birmingham, in the county of Warwick, E England, electrical engineer, have invented certain new and useful Improved Means for Use in Controlling Induction- Motors, of which the following is a specification.

This invention relates to the typeof alternating current motor in which resistance which is to be out out as the motor increases in speed in starting, and to be brought in again as the motor slows down in stopping, is carried by and revolves with the rotor," and mainly to that form thereof in whichl resistance is cut out by a brush which is moved by centrifugal force, acting against the force of a spring. In this particular form of this type of motor, as before devised, the centrifugal force increases in so mucl. greater roportion than the restrainlng force of t e spring that, as the speed of the rotor in increasing, the resistance is cut out, suddenly, and a great rush of current takes place, with resulting mischief.

Now, this invention has for its main object to provide that the centrifugal foice shall act upon the brush through yariable leverage whereby, at any speed which may be attained by the rotor during start-mg up, the proper amount of resistance only will have been cut out, in relation to such speed, and insure that fluctuation of current will be avoided or very largely so. The invention comprises, also, means by which, in lieu of automatic control of a motor of the above type, the motor may be controlled by hand.

In order that the invention may be clearly understood, and readily carried out in practice, we will now describe certain applications of the same, which are illustrated, by way of example, by the drawings, herewith, of which Figure 1 is a. vertical section, taken longitudinally of the axis of a motor, showing a form of the invention in which the resistance is cut out and brought in automatically in starting and stopping the motor, sufiicient only of the entire motor being shown to illustrate the application of the invention thereto- Fig. 2 is a section taken in the planes indicated by line a: of, Fig. 1, looking in the direction of the arrow 1 of such figure, the disk-plate B hereinafter described being omitted. Fig. 3 is a view.

as soon in a section taken on line ;1 y of F 1, looking in the direction of arrow 2 of such figure; Fig. 4 shows, in longitudinal sect-ion, means by which, according to this invention, the brushes may be operated Patented'Au'g. 26, i913.

across the faces of the disks by hand, so

as to out out resistance in starting u and to bring it in again in stopping; and, ig. 5 shows a View of the portion of the apparatus shown by Fig. 4, looking in the directron of the arrow 3 of such figure, the surrounding casing being omitted, and part of the view being in section.

Referring first to the means illustrated by Figs. 1, 2 and 3, a number of disks A (in the instanceshown three) are carried to revolve with the rotor. These disks are spaced apart from one another as shown, and are each made up, as to its main structure, by spirally winding around a core a a stri of metal forming convolutions a, etc., wit

suitable insulation between, the outer convolution bei surrounded by a rim 0: The strip metal 1s, preferably, formed with a corrugation a running along the middle thereof, which. is conveniently of V-shape, and thus when a strip has been wound up in the formation of a-disk, the coils are securely prevented from slipping sidewise in relation to one another. The coils of the respective disks form resistances for different phases of the rotor winding. These coils are shown as rings for convenience of drawing. The rims a of the disks are shown to have widened-out lugs (1*, which butt against one another and distance the disks apart as required. These rims are clamped together between a disk plate B, which is formed with a nave or boss I) and is fixed upon the hollow spindle C of the rotor, and a disk plate B, by means of bolts 0, the-whole structure thus described revolving with the rotor. (Z, etc, are the connectors between the resistance coils a and different phases of the rotor winding. Three brushes D, namely, one in respect of each disk A,- are shown as spectively, which are fixed at their other ends to a spindle E, and this spindle is journalcd in bearings of the disk plates B and B and is therefore carried around by speed has been attained, it has reached the position shown by full lines in such figure,

and the resistance is then all cut out. When the brushes are in their inmost position they are each stopped, as shown by Fig. 2, against a laminated copper brush F by a copper strip f of the brush having come thereagainst. The particular construction of the brushes and the means by which the contact is insured when the resistance is all cut out may, however, be varied as desired.

The brushes are caused to move automatically in a direction to-cut out resistance, by the centrifugal force of a weight which is carried around by the rotor, and the movement of this weight, under centrifugal force, is utilized in such manner that, at any given speed which may be attained by the rotor, in starting up, the proper amount of resistance only will have been cut out in'relation to such speed, whereby fluctuation of current will be avoided. According to convenient means for this purpose, a weight G (which is shown in Fig. 1, though it would not strictly appear in the section) is carried on the free end of an arm G which is pivoted to the disk plate B, and this arm against a plain surface of the inner edge of a lever or arm J which is rigidly fixed to the spindle E and subsequently the teeth of the cam engage in turn with the teeth of the lever. The cam-like device H and the lever J have their plain operative surfaces and sets of teeth so arranged in relation to the axes about which the cam-like device and lever, respectively, turn, that as the weight flies out, the leverage through which it operates the spindle E lessens in such ratio that at any given speed which may be attained by the rotor in starting up, the proper amount of resistance only will have been cut out, in relation to such speed, to insure that fluctuation of current will be avoided... The spindle is shown to be turned by the flying out of the weight against the force of a spring K which is fastened at one end to the disk plate B and at its other end to a lever or short arm K which is rigidly fixed to the spindle E. The weight isshown by Fig. 3 in its inward position in which the brushes will be in their outward positions in which they have brought in all the resistance, and the weight is shown by this figure by broken circle in its outward position, in which it will have brought the brushes into their positions in which they will have cut out all the resistance.

The lugs a of the rims a of the disks A are shown, by Fig. 1, as rabbet-ed into one another, for the purpose of centering the disks together; and the rims are each formed split at one side and are tightened up around the resistance coils a by bolts i which pass through ears 2'. The disks and brushes are inclosed within a fixed casing M, the inner side on of which is securely fixed to the main case of the motor. By causing the'brushes to move inward in cutting out resistance, the disks A may be clamped together, and between the parts which carry them, at points around their peripheries, without need for inserting insulation between them, the disks being otherwise entirely separated from one another by air spaces. By these means a very rigid construction is insured.

Referring now to the apparatus illustrated by Figs. 4 and 5: A lever N is pivoted at one end to the disk plate B between which and the disk-plate B the disks A whichhave the resistance coils therein are clamped, and this lever at its other or free end is formed with an inclined slot t-nerethrough, into which projects a stud e of the spindle E which carries the brushes, A spindle P is screwed through a bush R which is concentric with and fixed to the outer plate m of the case which surrounds the apparatus. On the outer end of this spindle P is fixed a hand-wheel P, and the inner end of the spindle passes easily through an opening 02. formed through the lever N and is surrounded by collars p which are at opposite sides of the'lever and allow sufiicient play of the lever,between them. If the hand-wheel is turned in one direction, the lever is moved outward and turns the spindle E in one direction, and, if the handewheel is turned in the opposite direction, the lever is moved inward and turns the spindle E in the opposite direction. The spindel P is always stationary, except when it is being turned by hand, and the lever N revolves around this spindle while the motor is running, all as will now be clearly understood.

Having fully described my invention, what I claim and desire to secure by Letters Patent, is

1. An induction motor of the alternating current type, comprising a rotor, a disk which is carried by and is concentric with the rotor, and contains a number of turns of narrow electric conducting material which surround the axis of the disk, insulation between the turns, a'brush which is carried.- by the rotor and is movable over a side face of the-disk and in moving thereover bears successively against the side edges of such turns, a wei ht which is carried by an arm which is itself pivotally carried by the rotor, a spring also carried by the rotor, which tends to prevent the weight flying out under centrifugal force, said weigi t, as the rotor is getting up speed, moving said brush centrifugal force, against the resist-- he spring, in a direction to cut out re mice, a lever which is rigid with said a ini and-a second lever also pivotally carried by the rotor, the movement of the said arm transmitted through the said. levers to the wing, and one of these levers having a cam surface which as the weight flies out i 1 contact with a cam surface of the other lever, whereby the outward movement of the weight acts upon the spring through a varying leverage and insures that resistance will at out in starting up the rotor so that, at any speed which has been attained, approximately only the resistance proper to be cut out for such speed will be cut out, and thereby fluctuation of current avoided or minimized.

2. An induction motor of the alternating current type, comprising a rotor, a disk for ear-h rotor phase, which is carried by and is concentric with the rotor and contains -a number of turns of narrow electric conducting material which surround the axis of the disk, insulation between the turns, a spindle which is carried by the rotor, a brush which is carried by the spindle, a cam which is also carried by the spindle, a

second spindle which is also carrled by th rotor, a weighted arm carried by the second spindle, a cam carried by the second spindle,

a spring which is carried by the rotor and tends to prevent the weight from flying out under centrifugal force, said cam which is carried by the second spindle being operated by the weight as it flies out under centrifugal force against the restraining effort of the spring and itself operating, under variable leverage, the cam which is carried by the first-mentioned spindle, substantially as and for the purpose set forth.

3. An induction motor of the alternating current type, comprising a rotor, a disk for each rotor phase, which'is carried by and is concentric with the rotor andcontains a number of turns of narrow electric conducting material which surround the axis of the disk, insulation between the turns, a spindle which is carried by the rotor, a brush whichis carried by the spindle and is movable over a side face of the disk and in moving thereover bears successively against side edges of such turns, a spindle which is screwed through a fixed part of the motor, a

' lever which is pivotally connected at one end with the rotor and atthe other end with an arm of the first-mentioned spindle and is also swiveled at a point intermediate its ends with the second-mentioned spindle whereby, when the second-mentioned spindle is screwed through said fixed part of the motor the lever itself is moved and turns the first-mentioned spindle on one or other direction of rotation thereby moving the brush across the face of the disk and cutting out or bringing in resistance.

4. An induction motor of the alternating current type, comprising a rotor, a disk which is carried by and is concentric with the rotor and contains a number of turns of narrow electric conducting material which surround the axis of the disk, insulation between the turns, a brush which is carried by the rotor, a weighted arm which is carried by the rotor, a cam which is carried by the weighted arm, a second cam which is carried by the.rotor, a spring which is carried by the rotor and tends to prevent the weight from flying out under centrifugal force, said cam which is rigid with the arm being operated by the weight as it flies out under effort of the spring, and itself operating, under variable leverage, the said second cam, for the purpose set forth.

5. An induction motor of the alternating current type, comprising a rotor, a disk which is carried by and is concentric with the rotor and contains a number of turns of narrow electric conductin material which surround the axis of the disk, insulation between the turns, a brush which is carried by the rotor and is movable over a side face of the disk and in moving thereover bears successively against side edges of such turns, a spindle which is screwed through a fixed part of the motor, a lever which is pivotally connected at one end with the rotor and at the other end with an arm which is rigid with and projects from the axis of the brush, and is also swiveled at a point intermediate its ends with said spindle, whereby, when said spindle is screwed through said fixed part of the motor, the lever itself is moved and turns the brush in one or other direction of rotation thereby moving it across the face of the disk and cutting out or bringing in resistance.

In witness whereof I have hereunto signed my name this 12th day of May 1911, in the presence of two subscribing witnesses.

NICOLO PENSABENE.

Vitnesses ROBERT G. Groves, FLORENCE M. WILLIAMS.

centrifugal force, against the restraining 

